A method and apparatus for transmitting cell load information in a wireless communication system is provided. A first eNodeB (eNB) of a first system receives cell load information of a cell in a second system, from a radio network controller (RNC) of the second system, and transmits the received cell load information to at least one second eNB of the first system. The first system may be an evolved UMTS terrestrial radio access network (E-UTRAN), and the second system may be an UTRAN.